I cant figure it out! If i am currently in an app, and open the app switcher and open another app, the screen goes black. The only option from there is to hit the off button which turns the screen off, then turn it back on and it's back to normal, but I still cant use the app switcher. And this only happens if im currently in an app, if i try to open an app using the app switcher and am at the home screen, it opens the app and works fine. Any ideas??

i figured it out. i started uninstalling all of my tweaks to find the culprit and it was DisplayCandy. In the settings page for display candy, there is an enable on/off switch for the app. i turned it off and assumed that that would work, well it sort of does. If you're not familiar with DisplayCandy, it will give give an effect to opening and closing an app, but also to the app switcher (that i didnt realize as i had it set to default). If the app is turned off, the opening and closing of an app no longer does the effect, however, the switcher (set as default which means it should be normal) still works. I tested this by changing the effect to something else like cube up. and the effect worked with the cube up and the screen didnt go black when i used the app switcher and the app was set to enable off. I then changed it back to default, and it gave me the black screen. So this lead me to conclude that the enable on/off doesnt dictate to the app switcher, and the default effect of the switcher was the culprit of getting the black screen. I am not sure if i got a update on that app recently, and wonder, is there a way to set up the phone to keep a list of when and what is installed,uninstalled or upgraded? then it would be easier to determine what new app/tweak is messing things up if you download/install a lot of apps/tweaks.

I dont know where or how to contact the developer, but this needs to be fixed! But since uninstalling displaycandy, i have noticed pretty signifigant improvement on going back to the normal effects from default and dont really miss displaycandy much.